history · 24 April 1942 · 82 years ago
Joseph Rochefort's cryptanalytic team based in Pearl Harbor, US Territory of Hawaii had intercepted Japanese Navy radio messages mentioning the existence of task forces bearing names such as MO Covering Force, MO Attack Force, RZP Occupation Force, RXB Occupation Force, etc. Rochefort would quickly arrive at the hypothesis that these task forces were organized for an attack in the Port Moresby, Australian Papua region.
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